WordPress/wp-includes/class-wp-hook.php

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<?php
/**
* Plugin API: WP_Hook class
*
* @package WordPress
* @subpackage Plugin
* @since 4.7.0
*/
/**
* Core class used to implement action and filter hook functionality.
*
* @since 4.7.0
*
* @see Iterator
* @see ArrayAccess
*/
Code Modernization: Add `AllowDynamicProperties` attribute to all (parent) classes. Dynamic (non-explicitly declared) properties are deprecated as of PHP 8.2 and are expected to become a fatal error in PHP 9.0. There are a number of ways to mitigate this: * If it is an accidental typo for a declared property: fix the typo. * For known properties: declare them on the class. * For unknown properties: add the magic `__get()`, `__set()`, et al. methods to the class or let the class extend `stdClass` which has highly optimized versions of these magic methods built in. * For unknown ''use'' of dynamic properties, the `#[AllowDynamicProperties]` attribute can be added to the class. The attribute will automatically be inherited by child classes. Trac ticket #56034 is open to investigate and handle the third and fourth type of situations, however it has become clear this will need more time and will not be ready in time for WP 6.1. To reduce “noise” in the meantime, both in the error logs of WP users moving onto PHP 8.2, in the test run logs of WP itself, in test runs of plugins and themes, as well as to prevent duplicate tickets from being opened for the same issue, this commit adds the `#[AllowDynamicProperties]` attribute to all “parent” classes in WP. The logic used for this commit is as follows: * If a class already has the attribute: no action needed. * If a class does not `extend`: add the attribute. * If a class does `extend`: - If it extends `stdClass`: no action needed (as `stdClass` supports dynamic properties). - If it extends a PHP native class: add the attribute. - If it extends a class from one of WP's external dependencies: add the attribute. * In all other cases: no action — the attribute should not be needed as child classes inherit from the parent. Whether or not a class contains magic methods has not been taken into account, as a review of the currently existing magic methods has shown that those are generally not sturdy enough and often even set dynamic properties (which they should not). See the [https://www.youtube.com/watch?v=vDZWepDQQVE live stream from August 16, 2022] for more details. This commit only affects classes in the `src` directory of WordPress core. * Tests should not get this attribute, but should be fixed to not use dynamic properties instead. Patches for this are already being committed under ticket #56033. * While a number bundled themes (2014, 2019, 2020, 2021) contain classes, they are not a part of this commit and may be updated separately. Reference: [https://wiki.php.net/rfc/deprecate_dynamic_properties PHP RFC: Deprecate dynamic properties]. Follow-up to [53922]. Props jrf, hellofromTonya, markjaquith, peterwilsoncc, costdev, knutsp, aristath. See #56513, #56034. Built from https://develop.svn.wordpress.org/trunk@54133 git-svn-id: http://core.svn.wordpress.org/trunk@53692 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2022-09-12 17:47:14 +02:00
#[AllowDynamicProperties]
final class WP_Hook implements Iterator, ArrayAccess {
/**
* Hook callbacks.
*
* @since 4.7.0
* @var array
*/
public $callbacks = array();
/**
* The priority keys of actively running iterations of a hook.
*
* @since 4.7.0
* @var array
*/
private $iterations = array();
/**
* The current priority of actively running iterations of a hook.
*
* @since 4.7.0
* @var array
*/
private $current_priority = array();
/**
* Number of levels this hook can be recursively called.
*
* @since 4.7.0
* @var int
*/
private $nesting_level = 0;
/**
* Flag for if we're currently doing an action, rather than a filter.
*
* @since 4.7.0
* @var bool
*/
private $doing_action = false;
/**
* Adds a callback function to a filter hook.
*
* @since 4.7.0
*
* @param string $hook_name The name of the filter to add the callback to.
* @param callable $callback The callback to be run when the filter is applied.
* @param int $priority The order in which the functions associated with a particular filter
* are executed. Lower numbers correspond with earlier execution,
* and functions with the same priority are executed in the order
* in which they were added to the filter.
* @param int $accepted_args The number of arguments the function accepts.
*/
public function add_filter( $hook_name, $callback, $priority, $accepted_args ) {
$idx = _wp_filter_build_unique_id( $hook_name, $callback, $priority );
$priority_existed = isset( $this->callbacks[ $priority ] );
$this->callbacks[ $priority ][ $idx ] = array(
'function' => $callback,
'accepted_args' => (int) $accepted_args,
);
// If we're adding a new priority to the list, put them back in sorted order.
if ( ! $priority_existed && count( $this->callbacks ) > 1 ) {
ksort( $this->callbacks, SORT_NUMERIC );
}
if ( $this->nesting_level > 0 ) {
$this->resort_active_iterations( $priority, $priority_existed );
}
}
/**
* Handles resetting callback priority keys mid-iteration.
*
* @since 4.7.0
*
* @param false|int $new_priority Optional. The priority of the new filter being added. Default false,
* for no priority being added.
* @param bool $priority_existed Optional. Flag for whether the priority already existed before the new
* filter was added. Default false.
*/
private function resort_active_iterations( $new_priority = false, $priority_existed = false ) {
$new_priorities = array_keys( $this->callbacks );
// If there are no remaining hooks, clear out all running iterations.
if ( ! $new_priorities ) {
foreach ( $this->iterations as $index => $iteration ) {
$this->iterations[ $index ] = $new_priorities;
}
return;
}
$min = min( $new_priorities );
foreach ( $this->iterations as $index => &$iteration ) {
$current = current( $iteration );
// If we're already at the end of this iteration, just leave the array pointer where it is.
if ( false === $current ) {
continue;
}
$iteration = $new_priorities;
if ( $current < $min ) {
array_unshift( $iteration, $current );
continue;
}
while ( current( $iteration ) < $current ) {
if ( false === next( $iteration ) ) {
break;
}
}
// If we have a new priority that didn't exist, but ::apply_filters() or ::do_action() thinks it's the current priority...
if ( $new_priority === $this->current_priority[ $index ] && ! $priority_existed ) {
/*
* ...and the new priority is the same as what $this->iterations thinks is the previous
* priority, we need to move back to it.
*/
if ( false === current( $iteration ) ) {
// If we've already moved off the end of the array, go back to the last element.
$prev = end( $iteration );
} else {
// Otherwise, just go back to the previous element.
$prev = prev( $iteration );
}
if ( false === $prev ) {
// Start of the array. Reset, and go about our day.
reset( $iteration );
} elseif ( $new_priority !== $prev ) {
// Previous wasn't the same. Move forward again.
next( $iteration );
}
}
}
unset( $iteration );
}
/**
* Removes a callback function from a filter hook.
*
* @since 4.7.0
*
* @param string $hook_name The filter hook to which the function to be removed is hooked.
* @param callable|string|array $callback The callback to be removed from running when the filter is applied.
* This method can be called unconditionally to speculatively remove
* a callback that may or may not exist.
* @param int $priority The exact priority used when adding the original filter callback.
* @return bool Whether the callback existed before it was removed.
*/
public function remove_filter( $hook_name, $callback, $priority ) {
$function_key = _wp_filter_build_unique_id( $hook_name, $callback, $priority );
$exists = isset( $this->callbacks[ $priority ][ $function_key ] );
if ( $exists ) {
unset( $this->callbacks[ $priority ][ $function_key ] );
if ( ! $this->callbacks[ $priority ] ) {
unset( $this->callbacks[ $priority ] );
if ( $this->nesting_level > 0 ) {
$this->resort_active_iterations();
}
}
}
return $exists;
}
/**
* Checks if a specific callback has been registered for this hook.
*
* When using the `$callback` argument, this function may return a non-boolean value
* that evaluates to false (e.g. 0), so use the `===` operator for testing the return value.
*
* @since 4.7.0
*
* @param string $hook_name Optional. The name of the filter hook. Default empty.
* @param callable|string|array|false $callback Optional. The callback to check for.
* This method can be called unconditionally to speculatively check
* a callback that may or may not exist. Default false.
* @return bool|int If `$callback` is omitted, returns boolean for whether the hook has
* anything registered. When checking a specific function, the priority
* of that hook is returned, or false if the function is not attached.
*/
public function has_filter( $hook_name = '', $callback = false ) {
if ( false === $callback ) {
return $this->has_filters();
}
$function_key = _wp_filter_build_unique_id( $hook_name, $callback, false );
if ( ! $function_key ) {
return false;
}
foreach ( $this->callbacks as $priority => $callbacks ) {
if ( isset( $callbacks[ $function_key ] ) ) {
return $priority;
}
}
return false;
}
/**
* Checks if any callbacks have been registered for this hook.
*
* @since 4.7.0
*
* @return bool True if callbacks have been registered for the current hook, otherwise false.
*/
public function has_filters() {
foreach ( $this->callbacks as $callbacks ) {
if ( $callbacks ) {
return true;
}
}
return false;
}
/**
* Removes all callbacks from the current filter.
*
* @since 4.7.0
*
* @param int|false $priority Optional. The priority number to remove. Default false.
*/
public function remove_all_filters( $priority = false ) {
if ( ! $this->callbacks ) {
return;
}
if ( false === $priority ) {
$this->callbacks = array();
} elseif ( isset( $this->callbacks[ $priority ] ) ) {
unset( $this->callbacks[ $priority ] );
}
if ( $this->nesting_level > 0 ) {
$this->resort_active_iterations();
}
}
/**
* Calls the callback functions that have been added to a filter hook.
*
* @since 4.7.0
*
* @param mixed $value The value to filter.
* @param array $args Additional parameters to pass to the callback functions.
* This array is expected to include $value at index 0.
* @return mixed The filtered value after all hooked functions are applied to it.
*/
public function apply_filters( $value, $args ) {
if ( ! $this->callbacks ) {
return $value;
}
$nesting_level = $this->nesting_level++;
$this->iterations[ $nesting_level ] = array_keys( $this->callbacks );
$num_args = count( $args );
do {
$this->current_priority[ $nesting_level ] = current( $this->iterations[ $nesting_level ] );
$priority = $this->current_priority[ $nesting_level ];
foreach ( $this->callbacks[ $priority ] as $the_ ) {
if ( ! $this->doing_action ) {
$args[0] = $value;
}
// Avoid the array_slice() if possible.
if ( 0 === $the_['accepted_args'] ) {
$value = call_user_func( $the_['function'] );
} elseif ( $the_['accepted_args'] >= $num_args ) {
$value = call_user_func_array( $the_['function'], $args );
} else {
$value = call_user_func_array( $the_['function'], array_slice( $args, 0, $the_['accepted_args'] ) );
}
}
} while ( false !== next( $this->iterations[ $nesting_level ] ) );
unset( $this->iterations[ $nesting_level ] );
unset( $this->current_priority[ $nesting_level ] );
$this->nesting_level--;
return $value;
}
/**
* Calls the callback functions that have been added to an action hook.
*
* @since 4.7.0
*
* @param array $args Parameters to pass to the callback functions.
*/
public function do_action( $args ) {
$this->doing_action = true;
$this->apply_filters( '', $args );
// If there are recursive calls to the current action, we haven't finished it until we get to the last one.
if ( ! $this->nesting_level ) {
$this->doing_action = false;
}
}
/**
* Processes the functions hooked into the 'all' hook.
*
* @since 4.7.0
*
* @param array $args Arguments to pass to the hook callbacks. Passed by reference.
*/
public function do_all_hook( &$args ) {
$nesting_level = $this->nesting_level++;
$this->iterations[ $nesting_level ] = array_keys( $this->callbacks );
do {
$priority = current( $this->iterations[ $nesting_level ] );
foreach ( $this->callbacks[ $priority ] as $the_ ) {
call_user_func_array( $the_['function'], $args );
}
} while ( false !== next( $this->iterations[ $nesting_level ] ) );
unset( $this->iterations[ $nesting_level ] );
$this->nesting_level--;
}
/**
* Return the current priority level of the currently running iteration of the hook.
*
* @since 4.7.0
*
* @return int|false If the hook is running, return the current priority level.
* If it isn't running, return false.
*/
public function current_priority() {
if ( false === current( $this->iterations ) ) {
return false;
}
return current( current( $this->iterations ) );
}
/**
* Normalizes filters set up before WordPress has initialized to WP_Hook objects.
*
* The `$filters` parameter should be an array keyed by hook name, with values
* containing either:
*
* - A `WP_Hook` instance
* - An array of callbacks keyed by their priorities
*
* Examples:
*
* $filters = array(
* 'wp_fatal_error_handler_enabled' => array(
* 10 => array(
* array(
* 'accepted_args' => 0,
* 'function' => function() {
* return false;
* },
* ),
* ),
* ),
* );
*
* @since 4.7.0
*
* @param array $filters Filters to normalize. See documentation above for details.
* @return WP_Hook[] Array of normalized filters.
*/
public static function build_preinitialized_hooks( $filters ) {
/** @var WP_Hook[] $normalized */
$normalized = array();
foreach ( $filters as $hook_name => $callback_groups ) {
if ( $callback_groups instanceof WP_Hook ) {
$normalized[ $hook_name ] = $callback_groups;
continue;
}
$hook = new WP_Hook();
// Loop through callback groups.
foreach ( $callback_groups as $priority => $callbacks ) {
// Loop through callbacks.
foreach ( $callbacks as $cb ) {
$hook->add_filter( $hook_name, $cb['function'], $priority, $cb['accepted_args'] );
}
}
$normalized[ $hook_name ] = $hook;
}
return $normalized;
}
/**
* Determines whether an offset value exists.
*
* @since 4.7.0
*
* @link https://www.php.net/manual/en/arrayaccess.offsetexists.php
*
* @param mixed $offset An offset to check for.
* @return bool True if the offset exists, false otherwise.
*/
#[ReturnTypeWillChange]
public function offsetExists( $offset ) {
return isset( $this->callbacks[ $offset ] );
}
/**
* Retrieves a value at a specified offset.
*
* @since 4.7.0
*
* @link https://www.php.net/manual/en/arrayaccess.offsetget.php
*
* @param mixed $offset The offset to retrieve.
* @return mixed If set, the value at the specified offset, null otherwise.
*/
#[ReturnTypeWillChange]
public function offsetGet( $offset ) {
return isset( $this->callbacks[ $offset ] ) ? $this->callbacks[ $offset ] : null;
}
/**
* Sets a value at a specified offset.
*
* @since 4.7.0
*
* @link https://www.php.net/manual/en/arrayaccess.offsetset.php
*
* @param mixed $offset The offset to assign the value to.
* @param mixed $value The value to set.
*/
#[ReturnTypeWillChange]
public function offsetSet( $offset, $value ) {
if ( is_null( $offset ) ) {
$this->callbacks[] = $value;
} else {
$this->callbacks[ $offset ] = $value;
}
}
/**
* Unsets a specified offset.
*
* @since 4.7.0
*
* @link https://www.php.net/manual/en/arrayaccess.offsetunset.php
*
* @param mixed $offset The offset to unset.
*/
#[ReturnTypeWillChange]
public function offsetUnset( $offset ) {
unset( $this->callbacks[ $offset ] );
}
/**
* Returns the current element.
*
* @since 4.7.0
*
* @link https://www.php.net/manual/en/iterator.current.php
*
* @return array Of callbacks at current priority.
*/
#[ReturnTypeWillChange]
public function current() {
return current( $this->callbacks );
}
/**
* Moves forward to the next element.
*
* @since 4.7.0
*
* @link https://www.php.net/manual/en/iterator.next.php
*
* @return array Of callbacks at next priority.
*/
#[ReturnTypeWillChange]
public function next() {
return next( $this->callbacks );
}
/**
* Returns the key of the current element.
*
* @since 4.7.0
*
* @link https://www.php.net/manual/en/iterator.key.php
*
* @return mixed Returns current priority on success, or NULL on failure
*/
#[ReturnTypeWillChange]
public function key() {
return key( $this->callbacks );
}
/**
* Checks if current position is valid.
*
* @since 4.7.0
*
* @link https://www.php.net/manual/en/iterator.valid.php
*
* @return bool Whether the current position is valid.
*/
#[ReturnTypeWillChange]
public function valid() {
return key( $this->callbacks ) !== null;
}
/**
* Rewinds the Iterator to the first element.
*
* @since 4.7.0
*
* @link https://www.php.net/manual/en/iterator.rewind.php
*/
#[ReturnTypeWillChange]
public function rewind() {
reset( $this->callbacks );
}
}